According to Build Your Own Hydraulic Forging Press by James L. Batson, a 5″ cylinder operating at 2,500 psi will generate 24.5 tons of hydraulic force. The power pack includes a 16 gpm two-stage pump and a 7.0 HP motor running at 3450 rpm. According to his book, this creates a ram speed of 3″ a second.
I have a chance to pick up a Vickers hydraulic power unit for $250. It has a 3 phase 5 hp motor running at 1730 rpm. The pump is a variable displacement piston ranging from 300 to 3000 psi. It is only 5gpm. Would it be too slow for a hydraulic forging press? I am shooting for a 15 to 30 ton press.
This unit comes with a 5' or 6' x 18ish' cylinder (exterior dimensions). No exact specs on the cylinder but I could always get a different cylinder. I am not an expert by any means on this and still learning alot on hydraulics. What you do have is a low presure pump. I have a H frame press which was converted with a low press cylinder 4' dia. And a 18' stroke, which is I was told about 13 ton.
It is slow but by prepositioning the ram were I want it helps alot. As Grant Sarver says you can do alot with 13 ton and he is absolutely right. I am building a 30 ton C frame high pressure but have not had much time to work on it. Grant, I have a sneaking suspicition that the o might be a Q which would lead me to think you have a 25VQ P2A, Not too terribly sure, the modle number you gave me is not lining up with any of the literature that im finding, but here are a couple of options for the 25V sieries vane pumps, hopefully one is right. And here is some info for Weld Inc's PVB5RSY20CC11, Looks like yours is a 5 GPM piston pump.
This is all that I have with me here at work, but when I get home I'll put up some more info that I have on flow rate VS pressures for the piston pumps. 5GPM is not a whole lot. The main issue that your facing is ram speed. In most typical home made forging presses a two stage gear pump is used.
In this setup the first stage supplies low pressure high volume (15 or so GPM @ 500 or less PSI). This stage supplies the volume that a moderate sized cylinder capable of providing sufficient forging force needs to move rapidly until the dies contact the workpiece. (4 to 6 inch diameter cylinder developing 24 to 40 tons with 1+ inches per second no load speed). When the dies hit the workpiece the pump shifts to the second stage. In the second stage the average pump will only typically move around 5 GPM at 2000-3000 PSI depending on what the relief valve is set to.
Your pump moving 5 GPM maximum will move a small ram at a set speed fast enough for forging, but the problem is that you will end up spending a lot of time waiting for the ram to cycle. The one cool thing about variable displacement piston pumps is that they are capable of moving from near 0 GPM up to there maximum rated output, therefore they are capable of building and *holding* pressures of up to 3000 PSI. Shvejnaya mashinka chajka 142m instrukciya skachatj besplatno. In a gear type pump, fluid pressure can not be stored easily due to the fact that the pump must constantly move fluid or they will over heat the fluid and stall the motor driving the pump, therefore most gear pumps idle at about 50 PSI while constantly recycling fluid from, and back to the resivoir. Because of this, you have to wait for a gear pump to build pressure (1-2 seconds). But with a piston pump a system can be charged to 3000 psi and have this pressure immediatly available.
Or you can store massive amounts of fluid under pressure (by using an accumulator). This is the direction that I have gone.
I am using a 15 GPM variable displacement pump and an 18 gallon accumulator. With this set up I am pushing a 10.25'diameter 18'stroke main cylinder, and a 5.5'diameter 22' stroke fast acting cylinder. The Accumulator should store enough fluid under opperating pressure to allow me to move the ram extremely fast when it is not under load. With the proper sized accumulator you should be able to complete numerous forging operations and have the system recover between forging cycles. The problem is that unless you have found a great place to scrounge it is typically cheaper and easier to set up a two stage gear pump.hope this helps. 5GPM is not a whole lot.
The main issue that your facing is ram speed. In most typical home made forging presses a two stage gear pump is used. In this setup the first stage supplies low pressure high volume (15 or so GPM @ 500 or less PSI). This stage supplies the volume that a moderate sized cylinder capable of providing sufficient forging force needs to move rapidly until the dies contact the workpiece.
(4 to 6 inch diameter cylinder developing 24 to 40 tons with 1+ inches per second no load speed). When the dies hit the workpiece the pump shifts to the second stage. In the second stage the average pump will only typically move around 5 GPM at 2000-3000 PSI depending on what the relief valve is set to. Your pump moving 5 GPM maximum will move a small ram at a set speed fast enough for forging, but the problem is that you will end up spending a lot of time waiting for the ram to cycle.